Sub base - Block paving substrate

[Sworddofthelord]

Hello,

i am wanting to widen my existing block paving drive and have an area to do which is 20 feet by 6 feet which i reckon is about 16m2

Can someone give me an idea how much hardcore or crusher run i need, how much sand for under the block paving, also what height does the blockpaving sit above the existing drive before wackering it down.
Hope i make sense i am new to this, thanks.

[Carberry]

Use these calculators

[JimmyD]

Hi. I have question that I hope someone on this forum can answer. Currently have an area that is covered with concrete slabs 450mmx450mmx50mm. Has vehicle traffic daily. Want to introduce block paving. Is it a good idea to use the concrete slabs as the sub-base. Budget issues. Have used it for years with very little sagging. There does not appear to be a sub-base (coarse material) beneath the slabs. Just compacted sand. Any advice would be most appreciated.

[Carberry]

Hi. I have question that I hope someone on this forum can answer. Currently have an area that is covered with concrete slabs 450mmx450mmx50mm. Has vehicle traffic daily. Want to introduce block paving. Is it a good idea to use the concrete slabs as the sub-base. Budget issues. Have used it for years with very little sagging. There does not appear to be a sub-base (coarse material) beneath the slabs. Just compacted sand. Any advice would be most appreciated.

Bad idea. If you decided to use those slabs as a sub base you would need to lift them, dig down, level the ground, lay them so there are no voids underneath then sand on top of the slabs then lay the block paving. It is much more effort doing that than doing the job correctly and your driveway will fail.
Take slabs up, dig down an extra 175-190mm, (150mm for sub base, 25-40mm for laying course). Minimum you need is 100mm sub base but recommend 150, it isn't that much more expensive.



Read this page and related pages for more information:
http://www.pavingexpert.com/blocks2.htm

[Citiheat]

Hi all, I have been watching this great site for a while now, not registering as all was going well with my block paved drive - apart from the weather - until now.
I dug out the 5m x 7m front garden (AKA drive to be), which was part concrete with 1" of poorly laid tarmac - but mostly garden, with a mini digger. Due to the shallow gas, electric and clay rain water drains, which were just at 250cm deep from the existing surface level, I couldn't slope it slightly more towards the neighbours garden on the left, bringing it in line with their concrete slab drive. Consequently this leaves my surface level flush with the top of my neighbours slab at the front of the garden, but 150cm higher at the house end. I now have a problem.... I have concreted in Acodrain along the front of the garden, which is level with the public footpath and the neighbours slab, but need to contain the MOT1 and sand etc where it is proud of the neighbours slab. I am using geo textile, 150mm MOT1, 100mm of sharp sand then 50mm Marley blocks. I am hoping to not to have to rip up my new fence and build a wall, but to have some kind of concrete foundation with the blocks on top or a dwarf wall 1 brick above block level, butting up to the fence. I am a good heating engineer, but not a professional paver (Obvious I know, but trying not to profess knowledge that I do not have. I laid my last drive, which was about the same size, but on a modern house with properly laid, non-1930s drains etc. This was very sucsessful, but the all of the edges were the same level as everything else important. I am very willing to take any advice offered, as not sure of the best direction or if I have the skills or logic required to invent my own solution - although I may yet have to.

Thank you in anticipation.

Regards,

Steve.

[Carberry]

Are you planning on a bedding layer of 100mm of sharp sand or is that a typo? If you are, that is way too much and it will fail within months, it should be 25-40mm of sand.

[Citiheat]

Sorry Carberry, typo. Must be the shock of realising that I don't know everything.
That should be 40mm of sharp sand.

[lutonlagerlout]

a picture would be handy citiheat
looks like you should have installed an edging or slab on edge retainer first before laying the blocks?
LLL

[Citiheat]

I'll go and tale a picture now Lutonlagerlout.

[Citiheat]

I now have photos. I just have to work out how to post them.

[lutonlagerlout]

create a photobucket account and upload them there
then using the settings on the brew cabin noticeboard click on the image tag and paste them here
800 by 600 is optimal size
cheers LLL

[Citiheat]

I can't find the settings, but this should work until I do. Note that the Acodrain is already in along with a heavy lump of concrete and an edging row of blocks. I intended to put another row of blocks on a bet of concrete after the type 1 was in and then haunch it. Regards, Steve.

1 Edge to be raised. String will be the finished surface.
http://i1297.photobucket.com/albums....39b.jpg

2 Next to dark brown fence is the highest point at 150cm above the neighbours concrete slab.
http://i1297.photobucket.com/albums....ad6.jpg

Left of fence is level with the neighbours concrete slab and the public footpath.
http://i1297.photobucket.com/albums....6ca.jpg

As no 1
http://i1297.photobucket.com/albums....6af.jpg

[lutonlagerlout]

put an edging in front of your fence to retain the drive
you can use 600 by 300 slabs where it gets high
cheers LLL

[mickg]

continue with the fence up to next doors house and bed a large key kerb along the line of the fence which will give you additional height you require, it will show a taper along the fence line from the house towards the aco drain at the pavement but be parallel with the new driveway

another way is to finish the fence and then fix a 7 x 2 treated timber to the finished height that the driveway will be and bed the edge detail of the driveway on a concrete bed
ie the height of your string line as shown on the photo

both of these will give lateral restraint for the block paving but bare in mind its timber and will rot over time, in the north west we normally use concrete posts and base panels with a timber infill but it seems the way fencing is erected in the south is the use of timber for all the fence even the posts a gravel boards

added
or as Luton says which is a cheaper option to use a concrete edging bedded and haunched in place with concrete

[Citiheat]

I'm a real beginner, what edging? Would that be a epp paving slab haunched in? And thank you for answering so quickly, especially so early in the morning. Regards, Steve.